Effects of salinity on antioxidant system in four grape (<i>Vitis vinifera</i> L.) genotypes

Abstract

Salinity is a major environmental stress that restricts plants growth and production. Grapes are classified as moderately sensitive to salinity. The aim of this work was to investigate the salinity effects on lipid peroxidation level, antioxidant compounds and anti-oxidative enzymes activities and photosynthetic pigment contents in four grape genotypes that are commonly grown in the region around Urmia salt lake. Malondialdehyde content and protective enzymes activities in roots and leaves of four genotypes increased significantly (P < 0.05) under salinity. 'Chawga' showed lower and higher increases in malondialdehyde content and enzymes activities, respectively. Salinity had an obvious effect on the accumulation of total phenolics content and induced phenylalanine ammonia-lyase enzyme activity in all genotypes. There were significant positive correlations (P < 0.01, r²= 0.838) between anti-oxidative enzyme activities, total phenolics content and phenylalanine ammonia-lyase activity in the leaves of all genotypes. Chlorophyll a, b contents in leaves of all genotypes were reduced and carotenoid content increased significantly (P < 0.05) under salinity. 'Chawga' showed a lower decrease in chlorophyll content and a higher increase in carotenoid content than others. It seems that 'Chawga' had a better antioxidant system compared to other genotypes and showed a higher capacity to tolerate salinity.